For retailers, protecting customer payment-card information is critical, and encryption is the typically the way to do that today. But Crutchfield Corp, which sells electronics and other goods online and through catalogs, has decided to migrate away from encryption in favor of an alternative security technology known as tokenization in order to shield sensitive customer data.

Guidelines for the tokenization process were spelled out last year by the PCI Security Standards Council, the reigning authority defining the network-security rules for any business handling credit and debit cards. The council's definition for use with payment cards says tokenization is "a process by which the primary account number (PAN) is replaced with a surrogate value called a token" and "de-tokenization is the reverse process of redeeming a token for its associated PAN value."

There are several vendors with tokenization technologies and Crutchfield has elected to go with the Voltage Secure Stateless Tokenization, the core of which is an appliance whose job is to convert the stored tokenized data back into readable form. It's offered as part of the Voltage SecureData Enterprise product which brings together encryption, tokenization, data masking and key management.

The advantage that Crutchfield sees in tokenization, according Alex Belgard, information security engineer there, is it eliminates the need to go through an encryption-key rotation process. "Today we have encryption in place, and we have to do key rotation annually and touch a lot of systems," Belgard says. He says one worry is the encryption keys could be stolen.

He also notes that the latest version of the Payment Card Industry (PCI) standard, which any business processing payment cards must follow, has some changes in it related to how to store an encrypted hash of a credit card that appear to add complexity to encryption use. Since tokenization is also an accepted PCI security practice to protect credit and debit cards, Crutchfield decided the time was right to shift away from encryption for PCI data and toward tokenization. The goal is to get this done in the spring timeframe before the next annual PCI assessment for Crutchfield is due.

Crutchfield retains customer payment card information for a limited time because it may be needed in the vent of a refund or other settlement process, and currently PCI data is encrypted by means of applications developed in-house that makes use of RSA-based encryption. But after the rush of the holidays is over, Crutchfield will be updating these applications in order to support a process of "bulk tokenization" of data through the Voltage product. To gain access to de-tokenized payment information, authorized users will need to gain secure access through the Voltage security appliance.

Voltage describes its tokenization technology as using a random-number generator based on static tables unique to each customer. The security firm says it uses tables to consistently produce a unique, random token for each clear text PAN input, resulting in a token that has no relationship to the original PAN. "The tokens are irreversible without the tokenization system." Voltage asserts, saying its process "withstands cryptanalyis."

Since the Voltage appliance will become a central touch point for payment-card security, Crutchfield will be treating the appliance as priority equipment, likely running it in redundant mode, geographically distributed, among other considerations.